This invention relates to an anesthesia machine, and more particularly, to an improved anesthesia machine wherein flowmeters are provided in the form of calibrated flowmeter modules including flowtubes floats and scales and wherein the flowmeter module is sealed with preventative means to discourage any alteration which could affect such calibration and integrity of the flowmeter module.
At present, normal anesthesia machines contain a plurality of needle valves for controlling the flow of oxygen and other various gases that are used to make up a respirable mixture for administration to a patient.
In addition to needle valves for such control, it is common to feature flowmeters including flowtubes, floats and flow scales through which the individual gases pass and which give the user a visual indication of the actual flow of that gas through the machine. It is not uncommon for such anesthesia machine to provide needle valves and flowmeters for gases including oxygen, nitrous oxide, CO.sub.2, helium and the like with individual control for each.
Such flowmeters include flowtubes that normally receive the gas at their bottom of such flowtubes and discharge the same at their top, and wherein a floating indicator within the flowtubes can be read from a scale located adjacent the tube. The tubes are individually calibrated and their installation and removal custom done, that is, the removal and replacement of any particular flowmeter requires skilled personnel accustomed to handling such equipment and further requires a recalibration of the flowmeter itself.
Because such flowmeters are individually factory installed and calibrated, there is considerable expense in manufacturing such anesthesia machines and, of course, in the later replacement and recalibration of any particular flowmeter.